Destructible cover for fragile dome



Feb. 26, 1957 s. JOHNSTON DESTRUCTIBLE COVER FOR FRAGILE DOME Filed Nov. 30, 1953 INVENTOR STEPHEN E. JOHNSTON ATTORNEY a Q Q k and the like.

7 be protected until the detector is to be used.

StatesPatent 70 r 2,782,716 D'E'srRU'c'rIBLE COVER 'FoR FRAGIL-E .noMn steplien E. Johnston, KanabpUtahfiassignor to .North A merican'Aviafiom Inc. A plicationNovember-30,inss seriaiNo.394,968

- retains. etioz ss 'This invention relates to fr ag'ile dom'es 'f'or enclosing radar antennae and' iiifrare'd radiation s'eanners and moi e particularly to a destructible cover providing an aerodynamic profile and prot'etibn forsu'ch In guidance syst'ems for'liyi'n'g rrii'ss'iles,iivhich systems rareimotivated by signals detected by. radar or infrared detectors, "afragile dome of glass, plastic,-, or the :likedsqiro- -vided foriprotection of the detector. elements [In -.ad di- :tion, 'for .infrared detectors the dome .n1ay oftenaet as ran element of the detector such..as.a,lens or np'rroreand therefore require special optical properties.

These domes, "when -"'subjected to =-1on flight, are susfi' eeptible to damage, by. wind, and trainierosion-por.shock The guidance system using this type of detector may not be scheduled for operation until the terminal portion of the flight and therefore the dome must It is also important to provide an aerodynamically clean" surface over the dome to improve the flight characteristics of the missile.

When the guidance system is to be used, any protective covering must be removed to permit operation of the detector. The simplest and most rapid method for disposing of the protective covering is to disintegrate or ex- ;plode it from the dome, but this is often diflicult to accomplish since the force required to remove the covering must not be of such an extent to damage the fragile dome. It is also notable that the protective covering must have sufficient strength to withstand the aerodynamic and external pressure loads imposed during flight. Providing this strength increases the force required to explode the covering and the attendant possibilities of damage to the dome are multiplied.

It is contemplated by this device to provide a protective cover for a fragile dome that provides an aerodynamic profile.

It is also contemplated by this device to provide a protective cover for a fragile dome that is easily and quickly disintegrated so as to expose said dome without damaging it.

It is therefore an object of this invention to provide a protective cover for a fragile dome.

It is another object of this invention to provide a cover for a fragile dome providing an aerodynamic profile.

It is still another object of this invention to provide an easily and quickly removable cover for a fragile dome.

It is a still further object of this invention to provide a destructible protective cover for a fragile dome which may be quickly removed without injuring said dome.

Other objects of invention will become apparent from the following description taken in connection with the accompanying drawings, in which:

Fig. l is an overall elevational view of a guided missile; and

Fig. 2 is an elevational view of the nose portion of the missile showing the preferred embodiment of this invention, partially broken away to show structure.

In detail, Fig. 1 shows a missile 16 having a nose por- 2,782,7 l 6 Patented :Feb. aaaear tion 17 housing a :guidancesystem and a tail portion i8 conventionally including stabilizing fins 19 and 'a propulsionmotor (=i1ot shown).

Fig. *2 shows a fragile, hemispherical dome. fi o'f plastic, glass, or the like which houses the d'etectingleme'nts (not shownyof the :radar or infrared guidance system. Surrounding said dome and "converging forwardly th'ereoils a thin-walledskin or s heath 1 which is scoremasat 7 to provide strip's -12 wl1ich (as to belatendescribedi) are adapted to be :peeled back toward -dome%6 like :the skin of a banana. Sheath 1 is also preferably scored at 8 adjacent dome 6 so that-strips 1-2 will break away from 'dome 6 when caught 'by the airstrearn. Surrounding the convergingends of strips 12 :a-nd secured jihercto as by 1 cementing is frangible :c'ap zafo'rmed :of plastic, pressed paper, or the like-and coming to a point li so "as t'o provide asuitablefaerodynarnic profilewith coverging sheath l. V

Housed within the forward en'd :of sheath :1 and cap c ean-explosive charge wliich maybe in the-form of pellet 5 having ignitionor-fuse wires 9 leading therefrom -to 3 -aiid oeeupying the space bet-weensaid pellet andadome 6 wi'thih s'he'ath 1 "and cap 2 is shock absorbent 'packin g,

' generally designated 14. As shown-in the drawing, packing 14 may be composed --of overlapping layers of felt a gas tightg shock absorbent pad. b eeupyihgam spaee 'within ca'p z pack-ing 14 may'wo'nsist of amass of paper pulp 4 having cardboard wad 10 separating it from felt blocks 5. It is obvious that packing 14 may consist of all felt blocks, all paper pulp, or of any shock-absorbent, gas-tight material. Packing 14 acts not only as a shock absorber for the protection of dome 6 but also acts to support sheath 1 and cap 2 to prevent their collapse due to external pressure or aerodynamic loads imposed during flight.

When it is desired to put into operation the detecting elements housed in dome 6, explosive pellet 3 is detonated by'ignition. The explosion shatters cap 2 and forces the converging ends of strips 12 outwardly while packing 14 protects dome 6 from damage. Strips 12 are then caught by the airstream and forced back and torn away to expose dome 6. That part of packing 14 not disposed of by the explosion of pellet 3 is carried away by the airstream.

Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of this invention being limited only by the terms of the appended claims.

I claim:

1. A destructible protective assembly for a fragile dome adapted to pass through a fluid comprising a closure converging over said dome, said closure having a forward part heading into said fluid, an explosive charge spaced from said dome and adjacent said forward part of said closure, and shock absorbent padding covering said dome whereby the explosion of said charge opens said closure, dispersing said padding and said closure so as to cause said fluid to expose said dome.

2. A destructible protective assembly for a fragile dome adapted to pass through a fluid comprising a sheath converging over said dome, spaced weakened portions in said sheath, a cap surrounding the converging end of said sheath, an explosive charge spaced from said dome and adjacent said cap and said sheath, and shock absorbent packing covering said dome whereby the explosion of said charge breaks said cap, dispersing said packing and said sheath so as to cause said fluid to expose said dome.

3. A destructible protective assembly providing an aerodynamic profile for a fragile dome adapted to pass through a fluid comprising a sheath converging over said dome and scored for peeling in strips, a frangible cap surrounding the converging end of said sheath, an explosive charge within said cap and spaced from said dome, and shock absorbent packing occupying the space be tween said charge and said dome whereby the explosion of said charge disintegrates said cap, dislodges said packing, and peels back said sheath so as to expose said dome.

. 4. In a missile guided by detecting means, in combination, a fragile dome for housing said'dctecting means, a sheath converging forwardly of said dome and scored for peeling in strips, a frangible cap surrounding the converging end of said sheath, an explosive charge withinsaid cap and spaced from said dome, and shock absorbent packing surrounding said charge and occupying thespace between said, charge and said dome whereby the explosion of said charge disintegrates said cap, dislodges said packing, and peels back said sheath so as to expose said dome without damage thereto.

5. In a guided missile having a fragile domeenclosing detecting elements, a protective nose cover providing an aerodynamic profile for said dome comprising a thinwalled converging skin, a frangiblecap surrounding the converging end of said skin, an explosive charge within said cap, and shock absorbent packing surrounding said charge whereby the explosion of said charge disintegrates said cap, dislodges said packing, and peels back said skin so as to expose said dome.

;; 6; In combination with a guided missile having a fragile dome enclosing detecting elements, a destructible protective assembly providing an aerodynamic profile for said dome comprising an explosive charge spaced from said dome, shock absorbent packing occupying the space between said charge and said dome, a sheath converging outwardly of said dome, encasing said charge and said packing, and scored for peeling in strips, and a frangible cap surrounding the converging end of said sheath whereby the explosion of said charge disintegrates said cap, dislodges said packing, and peels back said sheath so as to expose said dome without damage thereto.

7. A destructible protective assembly providing an aerodynamic profile for a fragile dome adapted to pass through a fluid comprising a sheath converging over said dome and scored for peeling in strips and for being broken away by the force of said fluid, a frangible cap surrounding the converging end of said sheath, an explosive charge within said cap and spaced from said dome, and shock absorbent packing occupying the space between said charge and said dome whereby the explosion of said charge and the force of said fluid disintegrates said cap, dislodges said packing, and peels back and breaks away said sheath so as to expose said dome.

References Cited in the file of this patent UNITED STATES PATENTS 1,201,763 Rimailho Oct. 17, 1916 1,552,435 Johnson Sept. 8, 1925 2,137,436 Barnhart Nov. 22, 1938 2,246,429 Brandt June 17, 1941 2,505,042 Gourdon Apr. 25, 1950 FOREIGN PATENTS 828,661 Germany Ian. 21, 1952 

